Your are lucky. Here in Denmark we have the CPR-number (det Centrale Person Register - the Central Person Register). Unfortunately this number is all to often used as authentication so is supposed to be kept secret. This is of course terribly broken and they get leaked all the time - also they are stamped onto everybody's national health insurance card[0]...
[0]: It's the "999999-9996" on https://i.imgur.com/GscmMjX.jpg